Method and apparatus for heating long blanks to forging temperature



W. B. PEIRCE. METHOD AND APPARATUS FOR HEATING LONG BLANKS T0 FORGINGTEMPERATURE.

APPLICATION FILED MAR. 81 I9I9.

Patented Nov. 22, 1921.

4 TTOHNE I 3 SHEETS-SHEET I.

W. a PEiRCE. 4 METHOD AND APPARATUS FOR HEATING LONG BLANKS T0 FORGTNGTEMPERATURE.

APPLICATION FILED MAR, 28, I9l9.

139?, wag Patented Nov, 22, MZL

A TTOR/VEY W. B. PEIHCE.

APPLICATION FILED MARx 28, I919.

Patented Nov. 22 1921.

3 SHEETSSHEET 3. L

METHOD AND APPARATUS FOR HEATING LONG BLANKS T0 FORGING TEMPERATURE.

UNITEDTSTATES PATENT OFFICE.

WILLIAM B. PEIRCE, OF NORTH TONAWANDA, ll'FlWv YORK.

METHOD AND APPARATUS FOR HEATING LONG BLANKS '10 FORGING TEMPERATURE.

Patented Nov. 22 1921,

Application filed March 28, 1919. Serial No. 285,860.

ments in Methods and Apparatus for Heating Long Blanks to ForgingTemperature, of which the following is a specification.

My present invention relates to the heat ing of metal blanks, preferablyto forging temperatures, the commercial and industrial purposes being insome respects quite similar to those set forth in my prior Patents Nos.1,243,442, 1,243,443 and 1,243,444. The material may be used insimilarly long lengths, as for instance, long rods in commercial bundlecoils as they come from the rod mills, and these lon lengths of materialmay be heated to simi arly high tempera tures, as for instance, for usein automatic bolt heading machines or nut punching and forming machines,in a relatively small furnace. But the method and the apparatus hereinset forth are radically different from those of my prior patents andthey possess certain peculiar advantages.

For instance, the auxiliary apparatus and machinery structurallyassociated with the furnace is reduced to a minimum, is much cheaper andsimpler to operate, and is less liable to get'out of order. p

Moreover, while my present method may be practised with rods of mediumor small diameter such as can be easily handled by methods of my priorpatents, my present method has special advantages when used for heatingthicker material, as for instance, rods halfan inch to an inch indiameter.

' My present method also has the advantage that material of half-round,square or other non-circular cross-section may be employed as easily asround rods, since the steps of the method are such that if desired, thecoiling of the material for compactness during heating and the uncoilingfor use can very easily be accomplished without any longitudinaltwisting or untwisting of the material. That is, if the material startsas an untwisted square bar, it can be delivered as an untwisted squarebar; or, if the original material has a twist, it can be delivered withthe ori 'nal twist unchanged. This is of particu ar advantage where flatbars sultable for nut blanks are to be heated and temperatures suitablevsupplied at forging temperatures to nut punching and the formingmachines.

One of the most important features of myv method is the forming of thematerial into open cylindrical coils and exposing the coils to the heatof the reverbatory furnace by rolling the coils on the floor or othersuitable SHPPOI't WIthiH the furnace. The open formation of the coilpermits direct penetration of radiant heat to all parts of the ma-.

terial as'well as free circulation of the flammg or hot gases intoheating contact therewith. The rolling of the bare coil has the effectof successively presenting all parts of the material at difierentelevations in the furnace, one for each revolution of the coil. Hence,whatever difference of heat there may be between the topmost level ofthe coil and the floor on which it rolls, that difference is equalizedand there is every op ortunity for soaking or internal conduction of theheat uniformly throughout the cross-section of the metal, therebyminimizing the danger of local overheating.

The success of this part of my method depends upon the fact that certainmaterials, particularly the iron and mild steel rods commonly used for'these purposes, when heated to a satisfactory forging softness, say 1700to 2000 Fahrenheit, still have enou h transverse or structural stiffnessso that the material will maintain its shape as an unflattened,undistorted helical coil with unimpaired rolling ability, provided thediameter of the coil be properly proportioned to the cross-section ofthe material. The length of the coil is not so important and it need beonly long enough for stability while rolling. The most desirable ratioof coil diameter to material diameter will depend somewhat on thequality of the metal and the temperatures to which it is to be heated,but for ordinary rods heated to good forging temperature, I have foundthat good results may in diameter for inch rods; about 6 to 7 inches forinch rods; say 7 to 71} inches for 4 inch rods; say 7% to 8 inches for 2inch rod and say 9 to 10 inches for 1 inch rod. These are merelysuggestive dimensions for the average commercial round rods.

Any of the above rod diameters will permit a coil diameter smaller thanthat named, since other things being equal, decreasing the diameter ofthe coil makes the turns stiflfer against collapse or flattening; 'It isbe had with coils 4 to 4% inches preferable to select the largest safediameter, however, since large diameter coils requlre less power forbending as well as less bending stress on the material in the coilforming machine; the large coils roll more easily over obstructions inthe furnacebed and are less likely to stick one against the other asthey roll; and the larger the diameter of the coil the greater length ofmaterial can be put in a single coil, with .a given clearance betweenadjacent turns.

It is to be noted that the determination of a safe coil diameter for agiven rod diameter, will depend on regulating, the heat of the furnaceand regulating the rate of progress of the coils through the furnace andthat the larger diameters Will be safer when these are regulated in suchmanner that the material will be gradually and uniformly heated to, butnot much beyond, the desired temperature. Too high furnace heat mayresult in too quickly heating the surface of the material to weldingtemperature so that adjacent coils will stick. and too slow progressthrough the furnace may result in overheating and collapse of the coil.

By my method, however, in which the turns of the coils are wellseparated and in which all portions of the coil successively roll intoand out of the upper regions-of greater heat, the heating is welldiffused and uniform throughout the whole cross-section of the metal. itis therefore comparatively easy for one skilled in such matters to keepthe heat within the rather wide, practically usable, limits of intensityand distribution.

My complete preferred method of which the above described coil heatingis an important feature involves taking desired lengths of the material,rounds, bars or flats,

- whether straight, bundle-coiled, or otherwise; forming the materialinto cylindrical helical coils having the adjacent turns slightlyseparated; utilizing the cylindrical shape of the coils for rolling themprogressively, preferably in continuous succes sion from the entrance tothe exit end of a suitable furnace; regulating the rate of theirprogress with reference to the heat, so that they will arrive at theexit end at the proper temperature for forging; then unwinding the coil;preferably reeling it oil at right angles to the axis of the coil, andwithdrawing the material endwise through a suitable exit opening in thefurnace; preferably rotating the coil once for every turn that isunwound, so that no twist is applied to the material. The progressiverolling of the coils in the furnace may be accomplished simply and very.effectively by making the floor of the furnace inclined and permittingthe coils to roll down toward the exit by gravity.

The essentials of the apparatus necessary for practice of my inventionwill be readily,

understood from the above description of the method, the principalessential being a coil forming machine adapted to wind heavy coils topredetermined desired diameters; a furnace of height dependent upon thediameter, of the coils and of length sufficient to contain the desirednumber of coils, an inclined floor for the coils to roll on, a stop tohold back the train of coils while the last fully heated coil is beingunwound and preferably also an endwise insertible and removable mandrelor reel for free rotatable support of the latter coil during theunwinding. The mandrel axis and the stop are preferably water cooled.The coil former may be constructed along the lines of machines nowcommonly employed for coiling heavy helical springs.

The apparatus as well as the method may be more fully understood fromthe following detailed description in connection with the accompanyingdrawings, in which-- Figure 1 is a vertical crosssection of the furnaceapproximately on the line 1--1, Fig.

2, the coil of heated material being shown in elevation and the supporttherefor partly in elevation and partly in section;

Fig. 2 is a side elevation of the furnace with the inclined floor andsuccession of rolling coils indicated in dotted lines;

I Fig. 3 is a top plan view of the same parts including the dotted lineshowing of the interior; and g Fig. 4 is a detailed view of feed rollsfor drawing the material endwise from the furnace and feed it to anydesired metal cutting, punching, shaping or forging machine.

The furnace may be of the usual construction and materials comprisingmasonry preferably refractory, floor 1, walls 2, 3, roof 4, preferablysupported, stayed and bound together by a channel frame comprisinguprights 6 and horizontal members 7 held by tie-bolts 8. Means forsupplying the heating medium, preferably flaming gases from aregenerative furnace are arranged preferably at the rear of the furnaceas conventionally indicated at 9, 9.

The floorof the furnace is inclined downward from rear to front asindicated at 10 but preferably'has a horizontal portion 11 at the upperend adjacent a side door 12 through which the coils may be insertedendwise into the furnace. The coils 13, 13 are supplied in continuoussuccession and roll by gravity down the'inclined floor 10 by progressivesteps toward the lower end of the incline. The train of rolling coils isheld back and the lowermost coil successively per- These stops arepreferably in the form of inverted U-shaped pipes, the legs of whichslide in vertical passages through the bottom of the furnace and theupper horizontal portions of which withdraw into short horizontalrecesses in the bed of the furnace, when in the the lowermost position.These pipes are water cooled in any desired way, as for instance, bymounting them on crosspipes 18, 19 supplied in any suitable way as forinstance through pipe -20 pivoted at 21. Water supplied to the pivotpipe 21 flows through 20 supplying pipe 18 and through flexibleconnection 22, supplying pipe 19. In the arrangement indicated in thedrawings, the water flows in both directions from the center of thepipes 18, 19 and escapes from the end thereof, but any other desiredarrangement may be employed. The stops 14, 15 may be operated fromeither side of the furnace through rod 23 connected. by arm 24 withcross shaft 25 provided at the far side of the furnace with operatinglever 26. I

By this arrangement the lowermost coil uniformly and highly heatedduring its progress down the incline 10 is permitted to escape and rolla slight distance free from proceeding coils. In the lowermost positionit is in approximate alinement with the mandrel or unreeling support 27.The latter comprises a hollow shaft 28, a smaller pipe within the sameand adapted to be water cooled by water flowing outward through saidhollow shaft and returning through said inner tube.

" Mounted on the shaft 28 are the cylindrical drum or reel elements,preferably comprising castings formed with hubs 29, webs 30 andlongitudinal enlargements 31.

-. These members are preferably made in sections so that if onebecomeswarped or burned or worn before the others, it may be easily and cheaplyrenewed. The unreeling mandrel is supported on a trolley 32 traveling ontrack 33 and preferably operated power means diagrammatically indicatedas a pressure cylinder 34. When the unreeling mandrel is in positionwithin the furnace, the free end of the shaft 28 is supported by bearing35. The end of the mandrel where the material is unreeled is preferablysupplied with a face plate 36 adapted to rotate closely adjacent, and soclose the opening 37 in the wall of the furnace. The opposite opening 38is provided with a removable closure 39.

In operation, the coils of proper diameter suited to the thickness ofthe material. are charged endwise into the furnace at intervals whichare preferably equal to the time it takes to unreel and use up the coilat the lower end of the furnace. This maintains a continuous train ofcoils capable of rolling against each other and toward the lower end ofthe furnace by gravity. When the lowermost coil is sufiiciently heated,its redecessor having been used up, the man rel is withdrawnv endwise byoperating cylinder 34, the escapement stops are operated and thelowermost coil allowed to roll into alinement with the mandrel; Themandrel is then inserted to about the position shown in Fig. 1. The freeend of the coil is then engaged with the feeding out rolls of thedesired metal working machine, usually by rolls of the type indicated inFig. 4, the man- .drel is then slightly advanced until the flange member36 substantially closes the opening 37. The feed rolls are then operatedto unwind and straighten the coil without twisting it until the materialof that coil its side, and rolling the bare coil progressively upon itsown periphery-along a suitable support ina reverberatory furnace.

2. The method of heating lengths of material which method consists inrolling bare coils thereof upon a stationary surface within a heatedfurnace, and feeding the heated material endwise of the material andlaterally with respect to the axis of the coil.

3. The method of heating material in lengths, which method consists informing the same in an open helical coil by winding or bending thematerial without twisting it, rolling the coil through a furnace to heatthe material and finally unrolling and simultaneously rotating the coilto remove the ma terial without twisting it.

4. The method .of heating long metal blanks which method consists informing the same into open helical coils, each long enough to make aself supporting roller when laid on its side, and rolling the coils upontheir own peripheries progressively through a reverberatory furnace.

5. The method of heating material in lengths which method consists informing the same in open helical coils by winding or bending thematerial without twisting it, rolling the coils in continuous successionthrough a furnace to heat the material and successively unrolling andsimultaneously is used up. Thereupon the mandrel is again cal coils, androlling the coils progressively through a reverberatory furnace, saidcoils being of diameter less than ten times the thickness of thematerial.

7. The method of heating long metal blanks to forging temperatures,which method consists in forming the same into open helical coils androlling the coils progressively through a reverberatory furnace, saidcoils being of such small diameter with reference to the diameter of themetal of the blank that it will substantially maintain its curvature andshape while so rolling at such forging temperatures.

8. A furnace for heating coiled rods, said furnace having a surface onwhich said coils may be rolled during heating, in combination with arotary mandrel arranged to project into the furnace, means whereby themandrel may be withdrawn endwise to permit moving of a coil intoalinement therewith and for advancing the mandrel endwise within saidcoil to rotatably support the same.

9. A furnace for heating coiled rods, said furnace having a surface onwhich said coils may be rolled during heating, in combination with arotary mandrel arranged to project into the furnace, means whereby themandrel may be withdrawn endwise to permit moving of a coil, and meansfor unreeling the material of the coil to straighten the same withoutimparting .any longitudinal twist thereto.

, 10. A furnace for heating coiled rods, said furnace having a rollwayalong which a plurality of said coils may be rolled with their axesparallel with each other during heating, in combination with a rotarymandrel arranged to project into the furnace, means whereby the mandrelmay be withdrawn endwise to permit sidewise rolling of the successivecoils into alinement therewith and for advancing the mandrel endwisewithin a fully heated coil to rotatably support the same.

11. A furnace for heatingcoiled rods, said furnace having a rollwayalong which a plurality of said coils may be rolled with their axesparallel with each other during 7 heating and means for freeing thelowermost coil from contact with the adjacent coil, in combination witha rotary mandrel arranged to project into the furnace, means whereby themandrel may be withdrawn eer/nos endwise to permit sidewise rolling ofsuccessive coils into alinement therewith and for advancing the mandrelendwise within said coil to rotatably support the same during unwinding.

12. A furnace for heating coiled rods, said furnace having a rollwayalong which a plurality of said coils may be rolled with their axesparallel with each other during heating, in combination with a rotarymandrel arranged to project into the furnace, means whereby the mandrelmay be withdrawnendwise to permit sidewise rolling of successive coilsinto alinement therewith and for advancing the mandrel endwise withinsaid coil to rotatably support the same, and means for unreeling thematerial of the coil to straighten the same without imparting anylongitudinal twist thereto.

13. A furnace for heating coiled rods, said furnace having an inclinedfloor of a width across the incline greater than the length of saidcoils and a length down the incline equal to the combined diameters of amultiplicity of said coils, a side door in the furnace adjacent theupper end of said incline through which said coils may be insertedendwise one at a time in position for rolling down said incline, meansfor stopping said coils above the lower end of said incline and forfreeing the lowermost coil from engagement with the preceding coil andan opening through which the material ofthe latter coil may be withdrawnendwise by progressive unwinding of the coil.

14. A furnace for heating coiled rods, said furnace having an inclinedrollway down which a plurality of said coils may roll by gravity in acontinuous trainwith their axes parallel with each other, and means forfreeing the lowermost coil from the coil behind it, in combination witha rotary mandrel arranged to project into the furnace, means whereby themandrel may be Withdrawn endwise to permit sidewise rolling of saidlowermost coil into alinement therewith and for advancing the mandrelendwise within said coil to rotatably sup- WILLIAM B. PEIRGE.

